aerogel

Light as air, stronger than steel and more flexible than rubber. Sound like something from the next installment of the Iron Man series? [Tony Stark] would certainly take notice of this fascinating technology. Fortunately for us, it does not come from the studios of Hollywood, but instead the halls of the NanoTech Institute at the University of Texas.

Professor [Ray Baughman] and his team of scientists at the NanoTech Institute have developed a type of artificial muscle through a process of making aerogel sheets by growing carbon nanotubes in a forest like structure. Think of a vertical bamboo forest, with each bamboo stem representing a single carbon nanotube. Now imagine that the individual bamboo stems were connected together by much smaller horizontal threads. So that if you dislodge the bamboo and began to pull, the threads would pull the others, and you would get this sheet-like structure.

These aerogel sheets of carbon nantubes have some truly science fiction like properties. They can operate from 1,600 degrees centigrade to near absolute zero. If you inject a charge, each nanotube will be repulsed from one another, expanding some 220% of the sheet’s original size. Your muscles do this at roughly 20 – 40%. Stick around after the break for a video demonstration of these carbon nanotube aerogel sheets being made and demonstrated.

The techniques behind producing aerogels have been on the Internet for a fairly long time. A few uncommon chemicals and a supercritical drying chamber are required for production, meaning it takes a lot of know-how to make hard air at home. Somehow, [Ben] got ahold of some tetramethoxysilane, the hard to come by ingredient and made a supercritical drying chamber out of pipe fittings and liquid Carbon Dioxide.

In the end, [Ben] was able to make a few small pieces of aerogel. The size of his pieces were constrained by his “mold” (actually a syringe) and the size of his drying chamber. It’s very possible [Ben] could build a larger supercritical drying chamber and make larger pieces of aerogel that would be sold commercially for hundreds of dollars.

Check out the very informative walkthrough of [Ben]’s process after the break. It’s 10 minutes long and makes for a great lunch break video.

Our own [Eliot] dug this one up from the grave. While the recipe has been online for a while, do you know many 10 year olds who made their own Aerogel, that wonderful insulator that’s essentially gelled air? [William] made some(cache) for his science project in 2002. He started with Silbond H5, a combination of ethyl alcohol and ethyl polysilicate. You can get the MSDS after a painless email registration on the Silbond website. After the gel is formed you have to soak it in an alcohol bath to make sure all water has been removed from the structure. Then the gel is placed in a drying chamber. Liquid CO2 is forced into the chamber to displace all the alcohol in the chamber and the structure. Once the the alcohol is gone the supercritical drying phase begins. The temperature is raised to 90degF and the pressure is regulated to 1050psi. At this point the liquid CO2 in the gel structure takes on gas properties (looses surface tension) and leaves the silica structure. All that remains in the chamber is your new Aerogel which is 99% empty space and 1000 times less dense than glass.